The present invention relates to a fastening element with an expansible member.
More particularly, it relates to a fastening element having a holding means arranged at the rear end for the purpose of fastening an article to a building component.
DE 44 33 918 A1 discloses a fastening element, which has, in the region of its forward end face, an expansible region formed by a longitudinal slot and an expansible element seated displaceably on the base of the longitudinal slot. The expansible element lies on the base of the longitudinal slot which has rises towards the forward end face. The outward face of the expansible member projects radially beyond the shaft of the fastening element and is provided with teeth. If, once the fastening element has been anchored, a drilled hole becomes enlarged through the formation of cracks, the shaft of the fastening element is displaced, by a tensile load acting on it with respect to the expansible member firmly seated in the wall of the drilled hole. As a result the enlargement of the drilled hole is compensated by means of the base of the longitudinal slot, which rises towards the forward end face. The known fastening element is therefore suitable for use in the tension zone, in which drilled holes may become enlarged through the formation of cracks.
When the known fastening element is driven into a drilled hole in a building component, the expansible member must, in order to avoid premature expansion, be supported against the shaft of the fastening element. For that purpose, the boundary of the longitudinal slot facing towards the rear end face of the fastening element is constructed as a stop surface transverse to the longitudinal axis. As a result, on the one hand a resource-intensive production process is required for making the longitudinal slot in the shaft. On the other hand the shaft of the fastening element is weakened in the region of the stop surface as a result of notching and the depth of the longitudinal slot in question, which weakening result in a reduction of the holding value of the known fastening element. Furthermore, when the fastening element is driven in, bore dust is scraped off the walls of the drilled hole by the forward end edge of the expansible member located within the longitudinal slot. The bore dust penetrates into the longitudinal slot and can jam the expansible member in the longitudinal slot in such a manner that displaceability and, as a consequence, further expansion can no longer be ensured or are impaired in the event of a drilled hole's becoming enlarged through the formation of cracks.